Plastic (PET) bottle cap attachment mechanism, designed with an elastic polyurethane cord, for example, that is commercially available and made by Pepperell Braiding Company. This Bottle Cap Attachment Mechanism connects any shape plastic (Types 1-5) threaded cap to any shape or size plastic (PET) Type 1 bottle or base.
Threaded cap types that may be attached by this mechanism include, but are not limited to, dome caps (as shown in Photograph 2), smooth caps, ribbed caps, brush caps, phenolic caps, tamper evident caps, spout caps and plastic dropper tip caps of any size. While preferred embodiments are shown using plastic threaded caps and bottles, the embodiments of this invention may also be used with aluminum or other forms of metal threaded or unthreaded caps and bottles.
The embodiments of this invention solve three main problems:                No more,        1. Lost Caps—eliminates lost or missing plastic bottle caps by keeping cap attached to bottle at all times.        2. Waste—reduces amount of plastic waste by keeping plastic cap attached to bottle at all times.        3. Inconvenience—alleviates need to reapply cap or hold in hand when walking, biking, driving or exercising by keeping cap attached to bottle at all times.        
Embodiments of this invention are different and better than existing plastic bottle cap holders because (i) it is simple and inexpensive to apply for the manufacturer and (ii) practical and not intrusive for the end consumer.
Other forms of plastic bottle cap holders;                Are more expensive to manufacture        May interfere with stacking on shelves or in pallets        May interfere with the mouth or chin during drinking        May leak (as is the case with some forms of flip tops and water bottle sport caps)        Are sometimes cumbersome to take on and off the bottle        Inhibit the flow of carbonated beverages        
Other bottle cap attachment mechanisms do not work well primarily due to design flaws, complexity and limited ease of use. Embodiments of this invention improve on other design flaws by creating a simple, inexpensive, almost unnoticeable, small single connection from the bottle's neck to the center of the plastic cap.